Many modern aircraft, as well as other vehicles and industrial processes, employ gas turbine engines for generating energy and propulsion. Such engines include a fan, compressor, combustor and turbine provided in serial fashion, forming an engine core and arranged along a central longitudinal axis. Air enters the gas turbine engine through the fan and is pressurized in the compressor. This pressurized air is mixed with fuel in the combustor. The fuel-air mixture is then ignited, generating hot combustion gases that flow downstream to the turbine. The turbine is driven by the exhaust gases and mechanically powers the compressor and fan via a central rotating shaft. Energy from the combustion gases not used by the turbine is discharged through an exhaust nozzle, producing thrust to power the aircraft.
Gas turbine engines contain an engine core and fan surrounded by a fan case, forming part of a nacelle. The nacelle is a housing that contains the engine. The fan is positioned forward of the engine core and within the fan case. The engine core is surrounded by an engine core cowl and the area between the nacelle and the engine core cowl is functionally defined as a fan duct. The fan duct is substantially annular in shape to accommodate the airflow from the fan and around the engine core cowl. The airflow through the fan duct, known as bypass air, travels the length of the fan duct and exits at the aft end of the fan duct at an exhaust nozzle.
In addition to thrust generated by combustion gasses, the fan of gas turbine engines also produces thrust by accelerating and discharging ambient air through the exhaust nozzle. Various parts of the gas turbine engine generate heat while operating, including the compressor, combustor, turbine, central rotating shaft and fan. To maintain proper operational temperatures, excess heat is often removed from the engine via oil coolant loops, including air/oil or fuel/oil heat exchangers, and dumped into the bypass airflow for removal from the system.
The compressor includes a number of rotors arranged along the central longitudinal axis. The rotors may each include a plurality of blades, which define a substantially annular flow path for incoming and compressed air. The rotors may be separated by spacers, which also may attach to each rotor. The spacers or rotors may also attach to the central rotating shaft.
As the gas turbine engine operates, the rotors and spacers may rotate along with the central rotating shaft. This rotation creates forces which can deform, expand, contract or translate certain gas turbine engine components, including spacers. These forces may be a function of rotational speed, temperature, pressure, mass or radial distance from the central longitudinal axis. Spacers constructed of a single material, or without a reinforcing apparatus, may suffer from poor deformation, expansion, contraction or translation properties during operation. They may also necessitate compromises in system weight or packaging. Further, it may be difficult to accurately control or predict the degree of deformation or translation.
Accordingly, there is a need for an improved spacer for a gas turbine engine.